U.S. patent application number 17/387501 was filed with the patent office on 2021-11-18 for surgical implant with guiding rail.
The applicant listed for this patent is Stryker European Operations Holdings LLC. Invention is credited to Christine Herrmann, Bryan D. Milz, Lee L. Thibodeau.
Application Number | 20210353426 17/387501 |
Document ID | / |
Family ID | 1000005742025 |
Filed Date | 2021-11-18 |
United States Patent
Application |
20210353426 |
Kind Code |
A1 |
Milz; Bryan D. ; et
al. |
November 18, 2021 |
Surgical Implant With Guiding Rail
Abstract
A prosthetic intervertebral spacer includes a body having a
front end, a rear end, an anterior side, a posterior side, a top
surface, and a bottom surface, and an arcuate interface extending
away from the body and being connected to the rear end and the
posterior side of the body. A method of inserting and positioning
the spacer includes engaging a tool to the interface, inserting the
spacer at least partially into the intervertebral disc space by
moving the tool along an insertion direction, and allowing the
spacer to rotate with respect to the insertion direction within the
intervertebral disc space while continuing to move the tool along
the insertion direction.
Inventors: |
Milz; Bryan D.; (Florida,
NY) ; Herrmann; Christine; (Fair Lawn, NJ) ;
Thibodeau; Lee L.; (Cumberland, ME) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Stryker European Operations Holdings LLC |
Kalamazoo |
MI |
US |
|
|
Family ID: |
1000005742025 |
Appl. No.: |
17/387501 |
Filed: |
July 28, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16244742 |
Jan 10, 2019 |
11076965 |
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17387501 |
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15869536 |
Jan 12, 2018 |
10182919 |
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16244742 |
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15266062 |
Sep 15, 2016 |
9867713 |
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15869536 |
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14475863 |
Sep 3, 2014 |
9445914 |
|
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15266062 |
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12894796 |
Sep 30, 2010 |
8858637 |
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14475863 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/4611 20130101;
A61F 2/4455 20130101; A61F 2/442 20130101; A61F 2002/2817 20130101;
A61F 2002/30843 20130101; A61F 2/4465 20130101; A61F 2002/30538
20130101; A61F 2002/2835 20130101; A61F 2002/30785 20130101; A61F
2002/4627 20130101; A61F 2002/30779 20130101; A61F 2002/30266
20130101; A61F 2002/3082 20130101; A61F 2002/3008 20130101; A61F
2002/30304 20130101; A61F 2002/30883 20130101; A61F 2002/30777
20130101; A61F 2002/30593 20130101; A61F 2002/30879 20130101 |
International
Class: |
A61F 2/44 20060101
A61F002/44; A61F 2/46 20060101 A61F002/46 |
Claims
1. (canceled)
2. A surgical tool comprising: a grasping portion including first
and second arms having proximal and distal ends, the distal ends
extending along a proximal-distal axis; a sleeve having an inner
surface, the sleeve being slidably disposed about the grasping
portion; a handle portion connected to the proximal ends of the
first and second arms, the handle portion having a rod actuator and
a sleeve actuator, the sleeve actuator connected to the sleeve to
slide the sleeve with respect to the first and second arms; and a
rod having a first end disposed adjacent the distal ends of the
first and second arms and a second end, the rod actuator connected
to the second end, such that actuation of the rod actuator slides
the first end of the rod along a proximal-distal path that is
laterally adjacent to the distal ends of the first and second
arms.
3. The surgical tool of claim 2, wherein the first and second arms
are flexibly connected to the handle portion such that the distal
ends of the first and second arms can move towards and away from
one another.
4. The surgical tool of claim 2, wherein each of the distal ends of
the first and second arms includes a projection facing toward the
opposite arm for engagement to an interface of a spacer.
5. The surgical tool of claim 4, wherein the distal ends of the
first and second arms are curved to mate with an interface of a
spacer.
6. The surgical tool of claim 2, wherein the handle portion
includes a grip and a shaft portion, the shaft portion having a
proximal end connected to the grip and a distal end connected to
the grasping portion.
7. The surgical tool of claim 2, wherein the sleeve actuator
includes a rotatable knob disposed on the handle portion.
8. The surgical tool of claim 2, wherein the rod actuator includes
a slidable switch disposed on the handle portion and a screw for
locking the slidable switch with respect to the handle portion.
9. A surgical method comprising: engaging a tool to an interface of
an implant, the interface defining a rail having a neck portion
connected to and extending away from a rear end of a body of the
implant, the rail further having a lip portion connected to the
neck portion, the lip portion being wider than the neck portion in
a direction extending between top and bottom surfaces of the body;
moving the tool along an insertion direction to insert the implant
at least partially into an intervertebral disc space between two
adjacent vertebrae; and sliding the tool along the rail while
moving the tool further along the insertion direction to allow the
implant to rotate with respect to the insertion direction within
the intervertebral disc space.
10. The method of claim 9, wherein the tool maintains its
engagement to the interface during the steps of moving and
sliding.
11. The method of claim 10, wherein the step of sliding the tool
includes allowing a front end of the implant to interact with an
annulus fibrosis of an intervertebral disc to cause rotation of the
implant with respect to the insertion direction.
12. The method of claim 11, further comprising positioning the
implant in an anterior aspect of the intervertebral disc space.
13. The method of claim 11, further comprising positioning the
implant such that a longitudinal axis of the implant is
substantially perpendicular to the insertion direction.
14. The method of claim 11, further comprising positioning the
implant such that a longitudinal axis of the implant is
substantially parallel to a medial-lateral axis of the
intervertebral disc space.
15. The method of claim 11, wherein the step of sliding includes
allowing the implant to rotate such that a longitudinal axis of the
implant is angled at approximately 80 degrees with respect to the
insertion direction.
16. The method of claim 9, further comprising a step of forming a
hole through only a portion of an annulus fibrosis while leaving
the remainder of the annulus fibrosis intact, and wherein the step
of moving includes inserting the implant through the hole.
17. The method of claim 9, wherein the insertion direction is
substantially parallel to a posterior-anterior axis of the
intervertebral disc space.
18. The method of claim 2, further comprising moving an inner
surface of a sleeve of the tool over a distal end of the tool;
19. A surgical method comprising: positioning a distal end of an
arm of a tool adjacent an interface of an implant, the interface
defining a rail having a neck portion connected to and extending
away from a rear end of a body of the implant, the rail further
having a lip portion connected to the neck portion, the lip portion
being wider than the neck portion in a direction extending between
top and bottom surfaces of the body; moving an inner surface of a
sleeve of the tool over the distal end of the arm to engage the
tool to the interface of the implant; moving the tool along an
insertion direction to insert the implant at least partially into
an intervertebral disc space between two adjacent vertebrae; and
sliding the tool along the rail while moving the tool further along
the insertion direction to allow the implant to rotate with respect
to the insertion direction within the intervertebral disc space,
wherein the interface of the implant includes a notch and the tool
includes a rod engageable to the notch, and further comprising a
step of engaging the rod to the notch to prevent relative rotation
between the implant and the tool, and a step of disengaging the rod
from the notch to allow relative rotation between the implant and
the tool.
20. The method of claim 19, wherein the sliding step takes place
after the rod is disengaged from the notch.
21. The method of claim 20, wherein the implant is at least
partially inserted with the rod engaged to the notch and at least
partially inserted with the rod disengaged from the notch.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 16/244,742, filed on Jan. 10, 2019, now U.S.
Pat. No. 11,076,965, which is a continuation of U.S. patent
application Ser. No. 15/869,536, filed on Jan. 12, 2018, now U.S.
Pat. No. 10,182,919, which is a continuation of U.S. patent
application Ser. No. 15/266,062, filed on Sep. 15, 2016, now U.S.
Pat. No. 9,867,713, which is a continuation of U.S. patent
application Ser. No. 14/475,863, filed on Sep. 3, 2014, now U.S.
Pat. No. 9,445,914, which is a continuation of U.S. patent
application Ser. No. 12/894,796, filed on Sep. 30, 2010, now U.S.
Pat. No. 8,858,637, the disclosures of which are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to spinal implants and methods
of implanting such implants. More particularly, the present
invention relates to a spinal implant having a guiding rail for
cooperating with an insertion instrument, as well as the methods
associated with implanting that implant.
[0003] Back pain can be caused by many different things, including
any one of several problems that affect the intervertebral discs of
the spine. These disc problems include, for instance, degeneration,
bulging, herniation, thinning of a disc, and abnormal movement, and
the pain that is experienced is generally attributable to friction
or pressure that inevitably occurs when one adjacent vertebra
exerts uneven pressure or when both adjacent vertebrae exert such
pressure on the disc. Oftentimes, disc problems lead to the
vertebrae impinging on one of the very many nerves located in the
spinal column.
[0004] One surgical method commonly utilized to correct such disc
problems is a fusion procedure where a surgeon fuses together
adjacent vertebrae in single or multiple levels. Different methods
(as well as apparatus for use in those methods) for such surgery
have been developed for performance on cervical, thoracic, or
lumbar vertebral bodies. These fusion procedures will be referred
to herein as interbody fusion or "IF." Traditional IF techniques
generally involve removing at least a portion of the troublesome
disc from the patient, inserting a spinal implant device into the
space to hold the graft material in place and to support the
vertebrae while solid bone mass forms therebetween, and adding bone
graft material into the interbody space between the vertebrae that
flank the disc. Oftentimes, the steps of inserting an implant and
bone graft material involve first packing the implant with the bone
graft material, and thereafter implanting that construct.
[0005] While IF is a long-established technique for correcting the
aforementioned disc problems, it is one that is constantly updated.
For instance, different implants have been created to suit specific
needs, and methods involving the insertion of such implants and the
preparation of the vertebrae to receive same are constantly
evolving. One major issue that has existed and will continue to
exist is the fact that visibility to the surgical site is often
hindered by the patient anatomy. For instance, in the cervical
section of the spine, the vertebral bodies are rather small and
surrounding patient anatomy, such as the esophagus and other body
parts, makes access to and visibility of the surgical site rather
difficult. This often hinders the surgeon in properly positioning
an implant with respect to the vertebrae. Furthermore, in many IF
procedures, the required manipulation of the patient anatomy,
distraction of the vertebral bodies, and preparation of the
vertebral bodies often results in significant scar tissue being
formed in the patient. This can be detrimental when performing any
subsequently required spinal procedures.
[0006] Thus, there exists a need for a spinal implant and method of
using the implant that improves upon these shortcomings.
BRIEF SUMMARY OF THE INVENTION
[0007] A first aspect of the present invention is a prosthetic
intervertebral spacer. In accordance with one embodiment of this
first aspect, the spacer includes a body having a front end, a rear
end, an anterior side, a posterior side, a top surface, a bottom
surface, and an arcuate interface extending away from the body and
being connected to the rear end and the posterior side of the
body.
[0008] In accordance with other embodiments of the first aspect,
the interface may include a rail including a neck portion connected
to the body and a lip portion connected to the neck portion. The
lip portion may be wider than the neck portion in the direction
extending between the top and bottom surfaces. The neck and lip
portions of the interface may form a T shape. Additionally, a notch
may be included in the interface, thereby separating the rail into
a first rail segment and a second rail segment. The first rail
segment may be disposed on the rear end of the spacer, and the
second rail segment may be disposed on the posterior side of the
spacer. The notch may extend in a direction substantially parallel
to a longitudinal axis of the spacer.
[0009] In accordance with still other embodiments of the first
aspect, the rear end of the spacer may be curved, so that in
certain cases, the curves of the rear end and the arcuate interface
may lie on concentric circles. In other embodiments, the front end
may be curved, and may include a steering element configured to
mate with an adjacent vertebral body to cause rotation of the
spacer during insertion. In certain embodiments, the steering
element may be a fin or a crease, and may be disposed at an angle
with respect to a longitudinal axis of the spacer. Still further,
the spacer may include at least one aperture extending between the
upper and lower surfaces. The aperture may allow for bone growth
inducing substances to be placed therein.
[0010] A second aspect of the present invention is another
prosthetic intervertebral spacer. In accordance with one embodiment
of the second aspect, the spacer includes a body defined by an
outer wall having a convexly curved front end, a convexly curved
rear end, a convex anterior side, a concave posterior side, a top
surface, and a bottom surface. The spacer further includes an
arcuate interface protruding from the outer wall and being
connected to the rear end and the posterior side of the body, where
the interface is a rail including a neck portion connected to the
body and a lip portion connected to the neck portion. The lip
portion has a first dimension greater than a second dimension of
the neck portion, and the outer wall has a third dimension greater
than the first dimension, the first and third dimensions extending
between the top and bottom surfaces.
[0011] In accordance with other embodiments of this second aspect,
the rail may further include a notch separating the rail into first
and second rail segments. The notch may extend in a direction
substantially parallel to the longitudinal axis of the spacer. The
first rail segment may be disposed on the rear end of the spacer,
and the second rail segment may be disposed on the posterior side
of the spacer. Further, the neck portion and lip portion of the
interface may form a T shape.
[0012] In other embodiments according to the second aspect, the
front end may include a steering element configured to mate with an
adjacent vertebral body to cause rotation of the spacer. The
steering element may be a fin or a crease. Additionally, the
steering element may be disposed at an angle with respect to the
longitudinal axis of the spacer. Finally, the spacer may include at
least one aperture extending between the upper and lower surfaces.
The aperture may allow for bone growth inducing substances to be
placed therein.
[0013] A third aspect of the present invention is another
prosthetic intervertebral spacer. This spacer according to the
third aspect may include a body having a front end, a rear end, an
anterior side, a posterior side, and a longitudinal axis. The front
end preferably mates with the anterior side at a transition portion
that is curved, the transition portion being configured to interact
with an annulus fibrosis of an intervertebral disc to cause
rotation in the spacer during insertion of the spacer. The spacer
may further include an arcuate interface extending away from the
body and being connected to the rear end and the posterior side of
the body. In certain embodiments, the interface may be a rail
including a neck portion connected to the body and a lip portion
connected to the neck portion, the lip portion being wider than the
neck portion in the direction extending between the top and bottom
surfaces.
[0014] A fourth aspect of the present invention is a surgical tool
for inserting and positioning a prosthetic intervertebral spacer in
the intervertebral disc space between two adjacent vertebrae. In
accordance with one embodiment of the fourth aspect, the tool
includes a grasping portion including first and second arms having
proximal and distal ends, the distal ends being separated by a
first dimensions; a sleeve having an inner surface, the sleeve
being slidably disposed about the grasping portion, at least the
portion of the inner surface having an inner dimension less than
the first dimension; a handle portion connected to the proximal
ends in the first and second arms, the handle portion having a rod
actuator and a sleeve actuator, the sleeve actuator connected to
the sleeve to slide the sleeve with respect to the first and second
arms; and a rod having a first end disposed adjacent the distal
ends of the first and second arms and a second end, the rod
actuator connected to the second end to slide the rod with respect
with to the grasping portion.
[0015] In accordance with other embodiments of the fourth aspect of
the present invention, the first and second arms may be flexibly
connected to the handle portion such that the distal ends of the
first and second arms can move toward and away from another.
Further, the first and second arms may also include proximal ends
separate by a second distance less than the first distance. Each of
the distal ends of the first and second arms may include a
projection facing toward the opposite arm for engagement to an
interface of the spacer. The distal ends of the first and second
arms may be curved to mate with the inner face of the spacer.
[0016] In still further embodiments, the inner dimension may be
greater than the second distance. The handle portion may include a
grip and a shaft portion, the shaft portion having a proximal end
connected to the grip and a distal end connected to the grasping
portion. Likewise, the sleeve actuator may include a rotatable knob
disposed on the handle portion. Still further, the rod actuator may
include a slidable switch disposed on the handle portion and a
screw for locking the slidable switch with respect to the handle
portion.
[0017] A fifth aspect of the present invention is a method of using
a surgical tool for inserting and positioning a prosthetic
intervertebral spacer in the intervertebral disc space between two
adjacent vertebrae. In accordance with one embodiment of this
aspect, the method may include the steps of providing a surgical
tool including a grasping portion having first and second arms
having proximal and distal ends, the distal ends being separated by
a first dimension; a sleeve having an inner surface, the sleeve
being slidably disposed about the grasping portion, at least a
portion of the inner surface having an inner dimension less than
the first dimension; a handle portion connected to the proximal
ends of the first and second arms, the handle portion having a rod
actuator and a sleeve actuator, the sleeve actuator connected to
the sleeve to slide the sleeve with respect to the first and second
arms; and a rod having a first end disposed adjacent the distal
ends of the first and second arms and a second end, the rod
actuator connected to the second end to slide the rod with respect
to the grasping portion. The method may also include the steps of
positioning distal ends of the first and second arms adjacent in
interface of an intervertebral spacer, moving the sleeve such that
the portion of the inner surface to the sleeve having the inner
dimension overlaps the distal ends of the first and second arms,
thereby engaging the tool to the interface of the spacer, and
engaging the first end of the rod to a notch in the spacer.
[0018] In accordance with other embodiments of the fifth aspect,
the method may further include the steps of inserting the spacer
into the intervertebral disc space, disengaging the first end of
the rod from the notch, and/or further inserting the spacer into
the intervertebral space when the rod is disengaged from the notch.
The tool may be configured to slide along the interface of the
spacer when engaged with the spacer, where the step of further
inserting the spacer includes sliding the tool along the interface
of the spacer while the spacer rotates in the intervertebral disc
space. Relative rotation of the spacer may be prevented when the
rod is engaged to the notch and permitted when the rod is
disengaged from the notch. The step of disengaging may be conducted
when the spacer contacts a portion of an annulus fibrosis in the
anterior portion of the intervertebral disc space.
[0019] In further embodiments, the method of the fifth aspect may
further include the step of forming a hole through only a portion
of the annulus fibrosis while leaving the remainder of the annulus
fibrosis in tact, where the step of inserting includes inserting
the spacer through the hole. The step of moving the sleeve may
include actuating the sleeve actuator. The method may further
include the step of tightening the grip of the tool on the spacer
by rotating a rotatable knob of the sleeve actuator. The step of
engaging the first end of the rod may include actuating a rod
actuator. The step of actuating may include sliding a slidable
switch through the road actuator with respect to the handle portion
and locking the slidable switch to the handle portion by tightening
the screw of the rod actuator. The method may further include the
step of disengaging the first end of the rod from the notch by
loosening the screw and sliding the slidable switch with respect to
the handle portion. The first and second arms of the tool may be
flexibly connected to the handle portion and the step of moving the
sleeve may cause the distal ends of the first and second arms to
move toward one another. In still further embodiments, each of the
distal ends of the first and second arms may include a projection
facing toward the opposite arm for engagement to an interface of
the spacer, and the step of moving the sleeve may cause the distal
ends of the first and second arms to engage the projections to
mating channels in the interface of the spacer. Additionally, the
handle portion may include a grip and a shaft portion, the shaft
portion having a proximal end connected to the grip and a distal
end connected to the grasping portion.
[0020] A sixth aspect of the present invention is another method of
using a surgical tool for inserting and positioning a prosthetic
intervertebral spacer in the intervertebral disc space between two
adjacent vertebrae. The method according to the sixth aspect may
include the steps of positioning distal ends of first and second
arms with a surgical tool adjacent an interface of intervertebral
spacer, the distal ends being separated by a first dimension,
moving a sleeve of the tool such that a portion of an inner surface
of the sleeve having an inner dimension less than the first
dimension overlapped the distal ends of the first and second arms,
thereby engaging the tool to the interface of the spacer, and
engaging a rod of the tool to a notch in the spacer.
[0021] In accordance with embodiments of the sixth aspect, the
method may further include the steps of inserting the spacer into
the intervertebral space, disengaging the rod from the notch,
and/or further inserting the spacer into the intervertebral space
when the rod is disengaged from the notch. In further embodiments,
the tool may be configured to slide along the interface of the
spacer when engaged with the spacer, with the step of further
inserting the spacer includes sliding the tool along the interface
of the spacer while the spacer rotates in the intervertebral disc
space. Relative rotation between the spacer and the tool may be
prevented when the rod is engaged to the notch and permitted when
the rod is disengaged from the notch. The step of disengaging may
be conducted when the spacer contacts the annulus fibrosis in the
anterior portion of the intervertebral disc space.
[0022] Further, the method of this sixth aspect, may further
comprise the step of forming a hole through only a portion of the
annulus fibrosis while leaving the remainder of the annulus
fibrosis in tact, where the step of inserting includes inserting
the spacer through the hole. The step of moving the sleeve may
include actuating the sleeve actuator of the tool thereby
tightening the grip of the tool on the spacer by rotating a
rotatable knob of the sleeve aperture. The step of engaging the rod
may include actuating the rod actuator of the tool, including
sliding the slidable switch of the rod actuator with respect to the
handle portion and locking the slidable switch to the handle
portion by tightening a screw of the rod actuator. The method may
further comprise the step of disengaging the first end of the rod
from the notch by loosening the screw and sliding the slidable
switch with respect to the handle portion. The first and second
arms of the tool may be flexibly connected to a handle portion of
the tool, and the step of moving a sleeve may cause the distal ends
of the first and second knobs to move towards one another. Each of
the distal ends of the first and second arms may include a
projection facing toward the opposite arm for engagement to an
interface of the spacer, and the step of moving the sleeve may
cause the distal ends of the first and second arms to engage the
projections to mating channels in the interface of the spacer.
[0023] A seventh aspect of the present invention is a method of
inserting and positioning a prosthetic intervertebral spacer in an
intervertebral disc space between two adjacent vertebrae. In
accordance with one embodiment of the seventh aspect, the method
may include the steps of providing a spacer including a body having
a front end, a rear end, a longitudinal axis, and an interface
extending away from the body and being connected to the rear end of
the body, engaging a tool to the interface; inserting the spacer at
least partially into the intervertebral disc space by moving the
tool along an insertion direction; and allowing the spacer to
rotate with respect to the insertion direction within in the
intervertebral disc space while continuing to move the tool along
the insertion direction.
[0024] In accordance with certain embodiments of the seventh
aspect, the tool may maintain its engagement to the interface
during the steps of inserting and allowing. The step of allowing
the spacer to rotate may include allowing the front end to interact
with an annulus fibrosis of an intervertebral disc to cause
rotation in the spacer with respect to the insertion direction. The
method may further include the step of forming a hole through only
a portion of the annulus fibrosis while leaving the remainder of
the annulus fibrosis in tact, where the step of inserting includes
inserting the spacer through the hole. The spacer may be inserted
such that the spacer is positioned in an anterior aspect of the
intervertebral disc space. The spacer may be inserted to a final
position where the longitudinal axis of the spacer is perpendicular
to the insertion direction. The longitudinal axis of the spacer may
be substantially parallel to a medial lateral axis of the
intervertebral disc space. The spacer may be inserted such that the
longitudinal axis of the spacer is rotated approximately 80 degrees
with respect to the insertion direction. The allowing step may
include allowing the tool to slide along the interface during
rotation of the spacer. The insertion direction may be
substantially parallel to a posterior-anterior axis of the
intervertebral disc space. The interface of the spacer may include
a notch and the tool may include a rod engageable to the notch,
where the method further includes the step of engaging the rod to
the notch to prevent relative rotation between the spacer and the
tool and the step of disengaging the rod from the notch to allow
relative rotation between the spacer and the tool. The allowing
step may take place after the rod is disengaged from the notch. The
spacer may at least be partially inserted with the rod engaged to
the notch and at least partially inserted with the rod from the
notch. The body may further include a top surface, a bottom
surface, and at least one aperture extending between the top and
bottom surfaces, where the method further includes the step of
packing bone graft material into the at least one aperture. The
spacer may further include a front end having frictional properties
that are greater than frictional properties of a rear end in the
spacer to aid in the rotation of the spacer within the
intervertebral space. The step of allowing the spacer to rotate
further may include allowing a steering element disposed on the
front end of the spacer to mate with one of the two adjacent
vertebral bodies to cause rotation of the spacer with respect to
the insertion direction. The steering element may be disposed at an
angle with respect to the longitudinal axis. The steering element
may be a fin or crease.
[0025] An eighth aspect of the present invention is another method
of inserting and positioning a prosthetic intervertebral spacer in
an intervertebral disc space between two adjacent vertebrae. In
accordance with one embodiment of the eighth aspect, the method may
include the steps of providing a spacer including a body having a
front end, a rear end, a longitudinal axis, and an interface
extending away from the body and being connected to the rear end of
the body, the interface including a notch; engaging a tool to be
interface, the tool including a rod; engaging the rod to the notch
to prevent relative rotation between the spacer and the tool;
inserting the spacer at least partially into the intervertebral
disc space by moving the tool along an insertion direction;
disengaging the rod from the notch; inserting the spacer further
into the intervertebral disc space after the disengaging step by
moving the tool substantially along the insertion direction; and
allowing the spacer to rotate with respect to the insertion
direction within the intervertebral disc space when the rod is
disengaged from the notch while continuing to move the tool along
the insertion direction.
[0026] In accordance with certain embodiments of the eighth aspect,
the method may further include the step of forming a hole through
only a portion of an annulus fibrosis while leaving the remainder
of the annulus fibrosis intact, where the step of inserting
includes inserting the spacer through the hole. The step of
allowing the spacer to rotate may include allowing the front end to
interact with an annulus fibrosis of an intervertebral disc to
cause rotation to the spacer with respect to the insertion
direction. The tool may maintain its engagement to the interface
during the steps of inserting and allowing. The spacer may be
inserted such that the spacer's position in an anterior aspect of
the intervertebral disc space. The spacer may be inserted to a
final position where the longitudinal axis of the spacer is
perpendicular to the insertion direction. The longitudinal axis of
the spacer may be substantially parallel to a medial-lateral axis
of the intervertebral disc space. The spacer may be inserted such
that the longitudinal axis of the spacer is rotated approximately
80 degrees with respect to the insertion direction. The allowing
step may include allowing the tool to slide along the interface
during rotation of the spacer. The front end of the spacer may
include a steering element, and the step of allowing the spacer to
rotate further may include allowing the steering element to mate
with one of the adjacent vertebral bodies to cause a rotation of
the spacer with respect to the insertion direction. The steering
element may be disposed at an angle with respect to the
longitudinal axis. The steering element may be a fin or crease. The
insertion direction may be substantially parallel to a posterior
that is entered axially in a vertebral disc space.
[0027] Further, the body may include a top surface, a bottom
surface, and at least one aperture extending between the top and
bottom surfaces, where the method further includes the step of
packing bone graft material into the at least one aperture. The
spacer may further include a front end having frictional properties
that are greater than frictional properties of a rear end of the
spacer to aid in the rotation of the spacer within the
intervertebral disc space. The first step of inserting may include
applying a force to the spacer along a first axis substantially
parallel to the longitudinal axis of the spacer, and the second
step of inserting may include applying a force to the spacer along
a second axis forming an angle with the axis of great than zero
degrees.
[0028] A ninth aspect of the present invention is another method of
inserting and positioning a prosthetic intervertebral spacer in an
intervertebral disc space between two adjacent vertebrae. In
accordance with one embodiment of the ninth aspect, the method may
include the steps of providing a spacer including a body having a
front end, a rear end, a longitudinal axis, and an interface
extending away from the body and being connected to the rear end of
the body; applying a force to a tool engaged to the interface to
move the spacer in the intervertebral disc space, the force being
directed along an insertion direction; and allowing the front end
to interact with an annulus fibrosis of an intervertebral disc to
cause rotation in the spacer with respect to the insertion
direction while continuing to move the tool along the insertion
direction.
[0029] In other embodiments of the ninth aspect, the method may
further include the step of forming a hole through only a portion
of the annulus fibrosis while leaving the remainder of the annulus
fibrosis intact, and the step of inserting the spacer through the
hole. The engaging between the tool and the interface may be
maintained during the steps of applying and allowing. The allowing
step may include allowing the tool to slide along the interface
during rotation of the spacer. The interface of the spacer may
include a notch and the tool may include a rod engaged to the
notch, where the method further includes the step of engaging the
rod to the notch to prevent relative rotation between the spacer
and the tool and the step of disengaging the rod from the notch to
allow relative rotation between the spacer and the tool. The
allowing step may take place after the rod is disengaged from the
notch. The spacer may be at least partially inserted with the rod
engaged to the notch and at least partially inserted with the rod
disengaged from the notch. The step of allowing may include
allowing a steering element disposed on the front end of the spacer
to meet with an adjacent vertebral body to cause rotation of the
spacer with respect to the insertion direction. The steering
element may be disposed at an angle with respect to the
longitudinal axis. The steering element may be a fin or a crease.
The step of applying may include the insertion direction being
substantially parallel to the longitudinal axis of the spacer and
the method may further include the step of applying a second force
to the spacer along the second axis forming an angle with the
longitudinal axis of greater than zero degrees.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] A more complete appreciation of the subject matter of the
present invention and the various advantages thereof can be
realized by reference to the following detailed description in
which reference is made to the accompanying drawings in which:
[0031] FIG. 1 is a front perspective view of a prosthetic
intervertebral spacer in accordance with one embodiment of the
present invention.
[0032] FIG. 2 is a top perspective view of the spacer shown in FIG.
1.
[0033] FIG. 3 is a top view of the spacer shown in FIG. 1, the
bottom view being a mirror image thereof.
[0034] FIG. 4 is a side view of the spacer shown in FIG. 1.
[0035] FIG. 5 is a cross-sectional view of a modified version of
the spacer shown in FIG. 1, the section being taken through the
modified version in a similar fashion to line X-X of FIG. 1.
[0036] FIG. 6 is a perspective view of a surgical tool for use in
inserting and positioning a prosthetic intervertebral spacer in
accordance with one embodiment of the present invention.
[0037] FIG. 7 is an exploded view of the insertion tool shown in
FIG. 6.
[0038] FIG. 8 is an enlarged exploded view of a portion of the view
of FIG. 7.
[0039] FIG. 9 is in illustration depicting an initial connection
between the spacer shown in FIG. 1 and the insertion tool shown in
FIG. 6.
[0040] FIG. 10 is an illustration depicting the spacer and
insertion tool construct shown in FIG. 9 with the insertion tool in
a locked position.
[0041] FIG. 11 is an illustration depicting the spacer and
insertion tool construct shown in FIG. 9 with the spacer rotated
with respect to the insertion tool.
[0042] FIG. 12 is an illustration of the spacer and insertion tool
construct shown in FIG. 9 with the spacer fully rotated with
respect to the insertion tool.
[0043] FIG. 13 is an illustration depicting the spacer and
insertion tool construct shown in FIG. 9 with the spacer released
from the insertion tool.
[0044] FIG. 14 is an illustration depicting the spacer and
insertion tool construct shown in FIG. 9 in relation to an
intervertebral space.
[0045] FIG. 15 is an illustration depicting the spacer and
insertion tool construct shown in FIG. 9 in relation to the
intervertebral space, with the spacer in a fully inserted
position.
[0046] FIGS. 16a-16g are illustrations depicting various stages of
insertion of the spacer shown in FIG. 1 in relation to the
insertion tool shown in FIG. 6 and a vertebral body.
[0047] FIG. 17 is a perspective view of a prosthetic intervertebral
spacer in accordance with another embodiment of the present
invention.
DETAILED DESCRIPTION
[0048] In describing the preferred embodiments of the subject
illustrated and to be described with respect to the drawings,
specific terminology will be used for the sake of clarity. However,
the invention is not intended to be limited to any specific terms
used herein, and it is to be understood that each specific term
includes all technical equivalents that operate in a similar manner
to accomplish similar purpose.
[0049] As used herein, when referring to bones or other parts of
the body, the term "proximal" means closer to the heart and the
term "distal" means more distant from the heart. The term
"inferior" means toward the feet and the term "superior" means
towards the head. The term "anterior" means towards the front part
of the body or the face and the term "posterior" means towards the
back of the body. The term "medial" means toward the midline of the
body and the term "lateral" means away from the midline of the
body.
[0050] Referring to FIGS. 1-4, there is shown a prosthetic
intervertebral spacer 10 in accordance with one embodiment of the
present invention. As shown, spacer 10 includes a body 12, which in
turn includes a front end 14, a rear end 16, an anterior side 18, a
posterior side 20, a top surface 22, and a bottom surface 24.
Spacer 10 further includes an interface 26, including a neck
portion 28, a lip portion 30, and a notch 32. Notch 32 separates
interface 26 into first and second segments 26a and 26b (best shown
in FIGS. 2 and 3), respectively. In the embodiment shown in FIGS.
1-4, interface 26 is arcuate and can best be described as a rail.
However, in other embodiments, interface 26 can vary in shape,
size, and configuration, with the only limitation being its
cooperation with an insertion tool, such as the one discussed more
fully below. Likewise, in the embodiments shown in FIGS. 1-4, notch
32 is shown as extending in a direction substantially parallel to a
longitudinal axis of spacer 10, and neck portion 28 and lip portion
30 are shown as forming a T-shape. Again, these elements can vary
in other embodiments.
[0051] Spacer 10 is preferably constructed of a polymeric material,
such as polyetheretherketone ("Peek"). However, spacer 10 may be
constructed of practically any materials suitable for implantation
in the body of a human. Front end 14 and rear end 16 are shown as
being curved, where the curves of the rear end and arcuate
interface 26 lie in concentric circles. Again, in other
embodiments, this configuration may vary. For instance, it is
contemplated to provide a substantially square or rectangular
shaped spacer 10. In the embodiment shown in FIGS. 1-4, front end
14 defines a tapered nose for spacer 10. However, in other
embodiments, front end 14 may (additional to or in lieu of the
tapered nose structure) include a steering element configured to
mate with at least one of the adjacent vertebral bodies spacer 10
is designed to be placed between in order to cause rotation of
spacer 10 during insertion. Such a steering element may include a
fin or crease, and may be disposed at an angle with respect to
longitudinal axis of spacer 10. One example spacer 110 of this type
is depicted in FIG. 17, in which a steering element 112 takes the
form of a crease. Of course, in other embodiments employing such a
steering element, other designs may be employed.
[0052] In the embodiment shown, top and bottom surfaces 22 and 24
each include a plurality of bone-engaging features in the form of
teeth 34. Other features may be employed for aiding in the fixation
of spacer 10 to the adjacent vertebrae. Spacer 10 also includes
apertures 36a and 36b formed through top and bottom surfaces 22 and
24. Apertures 36a and 36b are separated by a strut 38, which is
recessed with respect to both top and bottom surfaces 22 and 24. In
other embodiments, strut 38 may be formed flush with top and bottom
surfaces 22 and 24, or only recessed with respect to one or the
other. Apertures 36a and 36b are preferably designed to receive
bone growth material, as will be discussed more fully below.
Apertures 36a and 36b also exhibit an oblong shape in order to
avoid sharp corners that generally create engineering stresses and
may cause harm to the interior patient anatomy. Spacer 10 further
includes lateral fenestrations 40a and 40b, which are preferably
designed for allowing fusion that develops between the upper and
lower vertebrae (through the spacer) to spread laterally as well,
and a plurality of vertical markers 42a and 42b, which are
preferably constructed of tantalum and press fitted into spacer 10.
Markers 42a and 42b make the visual identification of spacer 10
easier through a traditional X-ray technique.
[0053] Spacer 10 shown in FIGS. 1-4 preferably includes a length
dimension from front end 14 to rear end 16 that is preferably
within the range of 15 mm to 40 mm, and more preferably between 26
mm and 31 mm, as well as a length dimension from front end 14 to
the end of interface 26 that is preferably within the range of 17
mm to 42 mm, and more preferably between 28 mm and 32 mm. A width
dimension from anterior side 18 to posterior side 20 of spacer 10
shown in FIGS. 1-4 is preferably in the range of 8 mm to 16 mm, and
more preferably approximately 12 mm. Spacer 10 shown in FIGS. 1-4
also preferably includes a height dimension from top surface 22 to
bottom surface 24 within the range of 6 mm to 15 mm. Of course, in
other embodiments, spacer 10 may be of any size. For instance,
spacers 10 designed for use in the cervical area of the spine may
be smaller than spacers 10 designed for use in the thoracic or
lumber spine.
[0054] Although shown in FIGS. 1-4 as having top and bottom
surfaces 22 and 24 situated in a parallel fashion with respect to
each other, FIG. 5 depicts a version of spacer 10 exhibiting top
and bottom surfaces 22 and 24 that taper from anterior side 18 to
posterior side 20. This tapered construction preferably aids in
restoring the natural lordotic angle of the adjacent vertebrae. The
angle of each taper is preferably within the range of zero to ten
degrees with respect to the midplane of spacer 10 to comport with
the natural lordotic angle, but may be any angle suitable for use
in the spine. The particular patient anatomy will generally
determine whether a spacer like that shown in FIGS. 1-4 or in FIG.
5 will be required. However, a surgeon may employ one design or the
other for other reasons.
[0055] FIGS. 6-9 depict an insertion tool 50 for use in inserting
and positioning a prosthetic intervertebral spacer, for instance,
above-described spacer 10, in the intervertebral disc space between
two adjacent vertebra. As is more clearly shown in the exploded
view of FIGS. 7 and 8, insertion tool 50 includes a grasping
portion 52 having first and second arms 54a and 54b that are
preferably capable of moving with respect to one another. In the
particular embodiment shown, arms 54a and 54b act as spring clips
having proximal ends attached to other portions of grasping portion
52 and distal ends between which the dimension can be varied. In
other embodiments, arms 54a and 54b may be movable in other
fashions, such as rotatable or the like. Tool 50 further includes a
sleeve 56 having an inner surface 57 that is slidably disposed
about grasping portion 52. A portion of inner surface 57 of sleeve
56 includes opposing surfaces that are preferably spaced apart by a
dimension that is less than a resting dimension between the outer
portions of arms 54a and 54b. This allows for the distance between
arms 54a and 54b to be reduced upon sliding of the sleeve distally.
This preferably allows for arms 54a and 54b to be in an initial
position, such as separated by the resting dimension, where they
are able to receive spacer 10, and where sliding of sleeve 56
causes arms 54a and 54b to affix to interface 26. In this regard,
arms 54a and 54b each preferably include projections 58a and 58b,
respectively, for positioning adjacent to the shoulder formed
between neck portion 28 and lip portion 30 of interface 26.
Moreover, arms 54a and 54b and projections 58a and 58b are
preferably curved to properly mate with the curvature of interface
26 and therefore to allow rotation of spacer 10 with respect to
tool 50. The rotational relationship between spacer 10 and tool 50
will be discussed more fully below.
[0056] As best shown in FIG. 6, tool 50 further includes a handle
portion 60 connected to grasping portion 52. Handle portion 60
preferably further includes a sleeve actuator 62 for causing
sliding movement of sleeve 56. In the embodiment shown, sleeve
actuator 62 includes a rotatable knob, the rotation of which causes
the sliding of sleeve 56. Handle portion 60 also preferably
includes a rod actuator 63 for causing movement of a rod 64 (best
shown in FIGS. 7 and 8) that acts as a rotational lock for spacer
10. In the embodiment shown, rod actuator 63 takes the form of a
switch, the sliding of which causes movement of rod 64. Handle
portion 60 also preferably includes a grip 66 that may be
ergonomically shaped and formed with a material suitable for
grasping by a surgeon.
[0057] FIGS. 9-13 depict the mating relationship between spacer 10
and insertion tool 50. With reference to FIG. 9, the initial
connection between spacer 10 and tool 50 is depicted. As noted
above, arms 54a and 54b are preferably in an initial state suitable
for receiving interface 26 of spacer 10. With reference to FIG. 10,
the inserter is shown with sleeve 56 slid over arms 54a and 54b to
affix spacer 10 to tool 50. In addition, rod 64 is shown deployed
into notch 32. Thus, spacer 10 can neither be removed from nor
rotated with respect to tool 50. FIG. 11 depicts spacer 10 rotated
with respect to tool 50. Essentially, in FIG. 11, rod 64 has been
disengaged from notch 32 through actuation of rod actuator 64. The
arcuate nature of interface 26 and arms 54a and 54b allows for the
rotation between the components. FIG. 12 depicts spacer 10 rotated
at a maximum amount with respect to tool 50. This amount is
approximately 80 degrees, but may be greater in other embodiments,
including approximately 90 degrees. Where FIGS. 9 and 10 depicted
the majority of tool 50 being connected with first segment 26a of
interface 26, FIG. 12 depicts the majority of tool 50 being
connected with second segments 26b due to the rotation of spacer 10
with respect to tool 50. Finally, FIG. 13 depicts spacer 10 having
been released from tool 50 upon sliding of sleeve 56 in the
opposite direction from which it is shown in FIGS. 10-12.
[0058] FIGS. 14 and 15 depict the spacer 10 and tool 50 construct
discussed above in relation to two adjacent vertebral bodies in the
spine of a human being. Although FIG. 14 depicts spacer 10 being
inserted from a posterior aspect of the spine, spacer 10 may be
inserted from any aspect. For instance, in other embodiments,
spacer 10 is inserted from an anterior aspect of the spine.
Likewise, although shown in FIG. 15 in a final position located in
an anterior portion of the intervertebral disc space, spacer 10 may
ultimately be disposed in many different areas of that
intervertebral disc space. For example, spacer 10 may ultimately be
implanted so as to be located in a posterior portion of the
intervertebral space.
[0059] FIGS. 16a-16g depict in more detail one embodiment method of
inserting and positioning spacer 10 in the intervertebral disc
space between two adjacent vertebra with the use of tool 50. Prior
to conducting the method shown in those figures, a surgeon
preferably forms a hole through the annulus fibrosis of an
intervertebral disc space, leaving a large amount of that
anatomical feature untouched. The surgeon may then remove (through
the formed hole or otherwise) certain material from the space in
order to allow for spacer 10 to be inserted therein. Thereafter, as
shown in FIG. 16a, the locked spacer 10 and tool 50 construct shown
in FIG. 10 is inserted through the hole formed through the annulus
fibrosis. Again, while this is shown in FIG. 16a as having occurred
from a posterior lateral aspect, other entry aspects may be
utilized in inserting spacer 10. Upon contact of spacer 10 with a
remaining portion of the annulus fibrosis (see FIG. 16b) rod
actuator 63 is actuated to withdraw the rotational lock provided by
rod 64 being disposed within notch 32. Spacer 10 is then allowed to
rotate with respect to tool 50 during further insertion of the
construct within the space, as front end 14 engages the remaining
portion of the annulus fibrosis. FIGS. 16c-16e depict subsequent
and sequential steps in this insertion process. FIG. 16f depicts
spacer 10 fully rotated with respect to insertion tool 50 and
disposed in an anterior portion of the disc space where, in this
embodiment, it shall remain. FIG. 16g depicts tool 50 being removed
from spacer 10. This is due to operation of sleeve actuator 62 to
slide sleeve 56 with respect to grasping portion 52. Spacer 10 is
now in its final position and tool 50 can be removed from the
space.
[0060] The methods of inserting spacer 10 may further include the
steps of packing apertures 36a and 36b with bone growth inducing
substances, such as bone morphogenetic proteins or natural bone
materials. In embodiments in which spacer 10 includes a steering
element, the rotation between spacer 10 and tool 50 may occur prior
to engagement of spacer 10 with the remaining portion of the
annulus fibrosis. In addition, it is to be understood that the
tapered nose of front end 14 of spacer 10 preferably aids in the
initial insertion of the spacer within the intervertebral disc
space, as well as the cooperation of the spacer with the remaining
portion of the annulus fibrosis.
[0061] Although the invention herein has been described with
reference to particular embodiments, it is to be understood that
these embodiments are merely illustrative of the principles and
applications of the present invention. It is therefore to be
understood that numerous modifications may be made to the
illustrative embodiments and that other arrangements may be devised
without departing from the spirit and scope of the present
invention as defined by the appended claims.
* * * * *